Bag for flowable materials

ABSTRACT

A bag for containing flowable materials, having a front panel, a rear panel coextensive with the front panel, and a pair of folded gussets. Each of the gussets has front and rear gusset layers joined at a central crease and a pair of outer gusset edges joined continuously along and to side edges of the front and rear panels. The bag has a bottom closure and at its initially open top portion, the front and rear gusset layers are joined to the respective front and rear panels along lines spaced from or adjacent to the joined side edges of the respective front and rear gusset layers and front and rear panels, to provide stiffened, fastened layer corner portions in the top portion of the open bag.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] This invention relates to bags for flowable materials, and, more particularly to deep gusseted bags for packaging granular, powdered, liquefied, and other such materials.

[0003] 2. Description of the Related Art

[0004] Packaging procedures for various types of granular or powder materials currently in use involve the use of deep gusseted bags pre-formed of various plastic films and other film or sheet materials. Individual bags are seized and the top ends thereof are drawn up over a material discharge chute positioned above a conveyor belt or other support at a filling station. The bag is filled with a metered amount of fill material and then tamped against the conveyor belt or support so that the weight of the fill material forms the bottom of the bag and product into a flat, squared configuration. The filled bag is released from the discharge chute and advanced on the conveyor belt from the fill station to a top closure station at which the top portions of gussets, previously unfolded by the filling operation, are refolded and the top of the bag sealed by a single heat fusion weld, for example.

[0005] The refolding of the top of a bag at the closure station is typically carried out by automated refolding blades that move into the top of the bag and then laterally to bring the unfolded gussets back to their folded condition, but it is also common practice to refold the gussets manually. Although the unfilled top portion of the bag is generally maintained in an upright orientation solely as a result of resistance of the previously folded bag material to bending, and is thus presented to the refolding blades at the closure station, the unfolded top of the bag may flex under its own weight or due to air movement between the filling station and the closure station so that it cannot be engaged properly or completely by the refolding blades. As a result, the top of the bag is often not properly refolded and the integrity of the closure seal is compromised. Also, the aesthetic appearance of the package represented by the filled and sealed bag is degraded when an uneven refolding of the gussets occurs.

SUMMARY OF THE INVENTION

[0006] The advantages and purpose of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The advantages and purpose of the invention will be realized and attained by means of the elements and combinations particularly pointed out in the appended claims.

[0007] To attain the advantages and in accordance with the purpose of the invention, as embodied and described herein, the invention is directed to a bag for containing flowable materials having a front panel, a rear panel opposite the front panel, and a pair of folded gussets. Each of the gussets has interconnected front and rear gusset layers and a pair of outer gusset edges joined continuously along and to the side edges of the front and rear panels. The bag has a bottom closure and at its initially open top portion, the front and rear gusset layers are joined to the respective front and rear panels to provide stiffened corner portions in the top portion of the open bag.

[0008] Additional objects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention will be realized and attained by means of the elements and combinations particularly pointed out in the appended claims.

[0009] It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention, as claimed.

BRIEF DESCRIPTION OF THE DRAWINGS

[0010] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate several embodiments of the invention and together with the description, serve to explain the principles of the invention. In the drawings,

[0011]FIG. 1 is a perspective view of a bag according to one embodiment of the present invention prior to filling;

[0012]FIG. 2 is a perspective view showing the bag of FIG. 1 after it is filled and prior to closing the top thereof;

[0013]FIG. 3 is a fragmentary perspective view illustrating an alternative gusset corner stiffening embodiment of the invention;

[0014]FIG. 4 is a fragmentary perspective view illustrating another alternative gusset corner stiffening embodiment of the invention

[0015]FIG. 5 is a fragmentary perspective view illustrating still another alternative gusset corner stiffening embodiment of the invention; and

[0016]FIG. 6 is a fragmentary perspective view illustrating a variation of the gusset corner stiffening embodiment shown in FIG. 5.

DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS

[0017] Reference will now be made in detail to the present embodiments of the invention, examples of which is illustrated in the accompanying drawings. Wherever possible, the same reference numbers will be used throughout the drawings to designate the same or like parts.

[0018] In accordance with the present invention, a bag is provided with a front panel, a rear panel coextensive with the front panel, and a pair of folded gussets. Each of the gussets has front and rear gusset layers joined at a central crease and a pair of outer gusset edges joined continuously along and to the side edges of the front and rear panels.

[0019] In the illustrated embodiments, as shown in FIG. 1, the bag, generally designated by the reference number 10, is formed by a folded tubular web to include a front panel 12 having top and bottom edges 14 and 16 and side edges 18, thus defining a front panel width and height. A rear panel 20 having top and bottom edges 22 and 24 and side edges 26 is coextensive with the front panel 12 and has a width and height the same as that of the front panel 12. A pair of folded gussets, each of which is generally designated by the reference number 28, extend throughout the height of the bag 10. Each of the gussets 28 have front and rear gusset layers 30 and 32 joined at a central crease 34, and a pair of outer gusset edges joined by folds continuously along and to the side edges 18 and 26 of the front and rear panels 10 and 20, respectively. As may be seen in FIG. 1, each gusset 28 has a width or depth to extend throughout a major portion of one half the width of the front and rear panels 10. Preferably, the depth of each of the gussets 28 is in the range of 30% to 50% of the bag width so that when unfolded upon filling the bag 10, the bag periphery approaches a square configuration.

[0020] In accordance with the invention, the bag includes a bottom closure and means for joining the front and rear gusset layers to the respective front and rear panels on diagonal lines extending from the bottom bag closure to the side edges of the front and rear panels so that, when the bag is filled, bottom portions of the gussets unfold and overlie folded bottom portions of the front and rear panels to define a square bag bottom.

[0021] In the illustrated embodiments, again as shown in FIG. 1, the bottom closure of the bag 10 is provided by a linear juncture 36 of the bottom ends 16 and 24 of the front and rear panels 10 and 20, and of the bottom ends of all gusset layers 30 and 32. When the bag 10 is formed of fusible material such as a thermoplastic film, the linear juncture 36 may be a fusion weld of the several layers represented by the front and rear panels 10 and 20, and the gusset layers 30 and 32. Alternatively, the juncture 36 may be formed by an adhesive material joining the several layers to each other.

[0022] The bottom portion of the bag 10 further includes diagonal linear junctures 38 that extend upwardly from the linear juncture 36 at approximately 450 to the side edges 18 and 26 of the front and rear panels 10 and 20. Unlike the juncture 36, the junctures 38 secure only the front and rear panels 10 and 20 to the front and rear gusset layers 30 and 32, respectively. The diagonal junctures 38 ensure that when the bag 10 is filled, as shown in FIG. 2, the unfolded gussets 28 overlie the squared bottom of the filled bag.

[0023] In accordance with the present invention, means is provided for joining top portions of the front and rear gusset layers to the respective front and rear panels along lines parallel to the joined side edges of the respective front and rear gusset layers and front and rear panels to provide stiffened, fastened layer corner portions in the top portion of the bag.

[0024] In the embodiment illustrated in FIGS. 1 and 2, at the top portion of the bag 10, the front panel 12 is secured to the front layers 30 of the gussets 28 along juncture lines 40 spaced slightly inwards and parallel to the side edges 18 of the front panel. Similarly, the rear panel 20 is secured to the rear layers 32 of the gussets 28 along juncture lines 42. As described above with respect to the linear juncture 36 at the bottom ends of the front and rear panels 10 and 20, when the bag 10 is formed of a fusible or thermoplastic film, the juncture lines 40 and 42 may be fusion welds of the front panel 10 and the gusset layers 28, but may be formed by an adhesive material joining the front panel and front gusset layers to each other.

[0025] The juncture lines 40 and 42 extend from the top edges 14 and 22 of the front and rear panels for a distance ranging from ¼ inch to approximately 50% of the bag height, preferably for a distance up to a distance representing a major portion of the bag 10 that is located above the top of flowable material that may be contained in the bag 10. The precise length of the juncture lines 40 and 42 will vary depending on the size of the bag, the anticipated fill level of the bag, and stiffness of the material from which the bag 10 is formed. In the embodiment of FIGS. 1 and 2, the juncture lines are approximately ¼ inch in width and spaced ¼ inch or less from the side edges 18 and 26 of the front and rear panels, though it will be understood from the description of alternative embodiments below, that the width, style, and location of the juncture lines 40 and 42 may differ from that embodiment. As such, the joined layers along the lines serve as linear stiffeners to ensure that when the bag 10 is filled, the four corners at the unfilled top of the bag will remain substantially erect for refolding the gussets 28 in preparation for sealing closure as shown in FIG. 2 of the drawings, and, in addition, will provide well-defined corners of the open bag that facilitate gusset refolding prior to sealing.

[0026] After the bag 10 is filled and sealed, the unfilled top portion of the bag shown in FIG. 2 may be folded or otherwise collapsed against the top of the fill material to square the top of the bag. To facilitate such collapse, a one-way vent valve 44, is provided in the top of the bag 10. Alternatively, the one-way vent valve 44 may be replaced by or simple vent hole, depending on the product to be packaged in the bag.

[0027] In FIGS. 3-6 of the drawings alternative embodiments of the stiffening juncture lines 40 and 42 are designated respectively by reference characters 40 a and 42 a, 40 b and 42 b, 40 c and 42 c, and 40 d and 42 d. Parts of the bag 10 previously described with reference to FIGS. 1 and 2 are designated by the same reference numbers in FIGS. 3-6.

[0028] In FIG. 3, the stiffening juncture lines 40 a and 42 a extend out to the side edges of the front and rear panels 12 and 20 and may range in width from less than ¼ inch to 2 inches, depending on the size of the bag, preferably from less than ¼ inch to ¾ inch. As in the embodiment of FIGS. 1 and 2, the stiffening juncture lines 40 a and 42 a are continuous. In the alternative embodiment of FIG. 4, the stiffening juncture lines 40 b and 42 b have the same width and orientation relative orientation relative to the side edges of the front and rear panels 12 and 20 as the stiffening juncture lines 40 a and 42 b, except that they are formed as interrupted or dashed lines that result in slightly spaced, intermittent fastenings.

[0029] In FIG. 5, the stiffening juncture lines 40 c and 42 c taper from a top width in the range of ¼ inch to 2 inches, depending on the size of the bag, preferably from less than ¼ inch to ¾ inch, downwardly to a point of merger with the side edges of the front and rear panels 12 and 20 at their bottom ends. In FIG. 6, the stiffening juncture lines 40 d and 42 d taper from a bottom width of comparable dimensions, upwardly to converge with the corner joining the side and top edges of the front and rear panels.

[0030] The bag of the present invention may be made of any of several commercially available film materials including but not limited to: polyethylenes including LLDPE, LDPE, MDPE, HDPE; metallocenes (linear and plastomer); polypropylene (oriented, BOPP); nylon; EVOH; syrloin; polyester, metalized films; and foil. Also, combination materials may be used, depending upon the product to be packaged in the bag. For example, some bags need to be gas flushed and retain the gas. In this instance, a coextruded material is used to retain the gasses and preserve the product for a longer period of time. Some products are hygroscopic, and require a moisture barrier that may be included in the tubular film web from which the bag is formed.

[0031] The films used to form the bag may vary in thickness in the range of from 1 to 10 mils, depending on the strength of the film used and the material to be packaged in the bag. For example, a relatively strong film, such as nylon, may be as thin as 1 to 3 mils, whereas the thickness of a polyethylene film having an equivalent strength may be in the range of from 4 to 8 mils.

[0032] Other embodiments of the invention will be apparent to those skilled in the art from consideration of the specification and practice of the invention disclosed herein. It is intended that the specification and examples be considered as exemplary only, with a true scope and spirit of the invention being indicated by the following claims. 

What is claimed is:
 1. A bag for containing flowable materials, comprising: a front panel; a rear panel opposite the front panel; a pair of folded gussets, each having interconnected front and rear gusset layers and a pair of outer gusset edges joined continuously along and to side edges of the front and rear panels; a bottom closure and an initially open top portion; and means for joining top portions of the front and rear gusset layers to the respective front and rear panels to provide stiffened corner portions in the top portion of the open bag.
 2. The bag of claim 1, wherein the top portions of the front and rear gusset layers are joined to the respective front and rear panels to provide fastened layers at the stiffened corner portions.
 3. The bag of claim 2, wherein the fastened layers extend from tops of the front and rear panels in a range of length up to approximately 50% of bag height.
 4. The bag of claim 2, wherein the fastened layers extend from tops of the front and rear panels for a distance representing a major portion of bag height located above a fill line for material to be contained in the bag.
 5. The bag of claim 2, wherein the fastened layers are joined for a width of joining in the range of from less than ¼ inch to 2 inches.
 6. The bag of claim 5, wherein the fastened layers are spaced inwardly from the side edges of the front and rear panels.
 7. The bag of claim 5, wherein the fastened layers are spaced inwardly from the side edges of the front and rear panels by ¼ inch or less.
 8. The bag of claim 5, wherein the fastened layers extend inwardly from the side edges of the front and rear panels.
 9. The bag of claim 6, wherein the width of fastened layers is constant throughout the length thereof.
 10. The bag of claim 8, wherein the width of fastened layers is constant throughout the length thereof.
 11. The bag of claim 9, wherein the fastened layers are joined continuously throughout the length thereof.
 12. The bag of claim 10, wherein the fastened layers are joined continuously throughout the length thereof
 13. The bag of claim 10, wherein the fastened layers are joined intermittently throughout at least a portion of the length thereof
 14. The bag of claim 8, wherein the width of fastened layers tapers from a top width to a point of merger with the side edges of the front and rear panels.
 15. The bag of claim 8, wherein the width of fastened layers tapers from a bottom width to a point of merger with the side edges at the tops of the front and rear panels.
 16. The bag of claim 1, formed of fusible film and wherein the means for joining the front and rear gusset layers to the respective front and rear panels comprises fusion welds.
 17. A bag for containing flowable materials, comprising: a front panel having top, bottom and side edges defining a front panel width and height; a rear panel having top, bottom and side edges defining a rear panel width and height the same as the front panel width and height; a pair of folded gussets extending between top and bottom gusset edges, each of the gussets having front and rear gusset layers joined at a central crease and a pair of outer gusset edges joined continuously along and to the side edges of the front and rear panels; a bottom bag closure; and means for joining top portions of the front and rear gusset layers to the respective front and rear panels along lines parallel to the joined side edges of the respective front and rear gusset layers and front and rear panels to provide stiffened double layer corner portions in the top portion of the bag.
 18. The bag of claim 17, wherein the folded gussets each have a length equal to the height of the front and rear panels, and a width equal to a major portion of one half the width of the front and rear panels.
 19. The bag of claim 17, wherein the bottom closure is formed by joining the bottom edges of the front and rear panels through the bottom gusset edges of both gusset layers.
 20. The bag of claim 17, further comprising: means for joining the front and rear gusset layers to the respective front and rear panels on diagonal lines extending from the bottom bag closure to the side edges of the front and rear panels so that, when the bag is filled, bottom portions of the gussets unfold and overlie folded bottom portions of the front and rear panels to define a square bag bottom. 